1. Field of the Invention
The present invention relates to an image processing apparatus for controlling access requests from a plurality of image input and/or output apparatuses that use the same memory to perform different data processes, a memory access method for the image processing apparatus, and a storage medium containing computer-readable programs.
2. Description of the Related Art
As to conventional image processing apparatuses of the above-described type, for example, copying machines having a plurality of functions are known. They have not only a copying function for printing scanned images, but also a plurality of functions such as a facsimile function for transmitting or receiving scanned images, and a communication function for establishing connection to a host unit and transferring image data to the host unit, or for loading and printing page-description-language (PDL) data.
In the functions, in general, image processing using an image-stored storage unit is performed. For example, in the process of copying, in order that image processes (electronic sorter) such as image rotation, and printing in changed order for making a pamphlet, may be performed, or in the facsimile function, in order that an image may be compressed or decompressed, or in operation-busy condition generated in the process of facsimile transmission or receiving, a storage unit is used as an image buffer for temporarily storing images. In addition, when printing from the host unit is performed, a storage unit is necessary as a spool function for storing a plurality of images in order to change the queue.
In the above-described conventional example, priority is assigned to each function of accessing the storage unit, and requests for accessing the storage unit are switched in units of image pages or blocks. Thus, a plurality of functions cannot simultaneously access the storage unit, so that the simultaneous operation of the functions cannot be realized.
In the case where a plurality of storage units are used, or the storage area of a single storage unit is divided into a plurality of storage blocks, and a plurality of functions can simultaneously access the separate storage units or storage blocks, the plurality of functions can simultaneously operate by the number of the storage units or the storage blocks. However, the cost of the storage units is increased by the addition. In addition, in this case, access requests are switched in units of image pages or blocks. Thus, it is impossible for a plurality of functions to access the same image, for example, simultaneous operation in which, while images are being stored from a scanner function into a storage unit, the images are transferred from the storage function to a printer function so as to be output.
Accordingly, the present invention has been made in order to solve the foregoing problems, and an object thereof is to provide: an image processing apparatus for arbitrarily setting image processing environments in which memory-access-job requests from a plurality of image input and/or output apparatuses are cyclically switched whenever a storage medium is accessed, whereby a single memory is used to simultaneously execute the memory-access-job requests from the plurality of image input and/or output apparatuses; a memory access method for the image processing apparatus; and a storage medium containing computer-readable programs.
To this end, according to a first aspect of the present invention, the foregoing object has been achieved through provision of an image processing apparatus for controlling access requests from a plurality of image input or output apparatuses for performing different data processes, the image processing apparatus comprising: a memory; and control means for cyclically switching memory-access-job requests from the plurality of image input and/or output apparatuses whenever the memory is accessed.
Preferably, when one memory-access-job request in succeeding order is not generated, the control means skips to execute the next memory-access-job request.
The image processing apparatus may further comprise first setting means for assigning high or low priority to one predetermined memory-access-job request from the plurality of image input and/or output apparatuses, wherein the control means executes the predetermined memory-access-job request in accordance with the high or low priority set by the first setting means.
The image processing apparatus may further comprise second setting means for assigning a consecutive access right to one predetermined memory-access-job request, wherein the control means executes the predetermined memory-access-job request by performing consecutive access.
When the memory is a refreshing storage device, the first setting means may assign the high priority to a refresh job request to the memory.
According to a second aspect of the present invention, the foregoing object has been achieved through provision of a memory access method for an image processing apparatus for controlling access requests from a plurality of image input and/or output apparatuses using a single memory to perform different data processes, the memory access method comprising the step of cyclically switching memory-access-job requests from the plurality of image input and/or output apparatuses whenever the memory is accessed.
According to a third aspect of the present invention, the foregoing object has been achieved through provision of a storage medium containing a computer-readable program for controlling an image processing apparatus controlling access requests from a plurality of image input and/or output apparatuses using a single memory to perform different data processes, the computer-readable program comprising the step of cyclically switching memory-access-job requests from the plurality of image input and/or output apparatuses whenever the memory is accessed.